The bilateral security agreement between the United States and Afghanistan has still not been signed, sealed and delivered, creating budget uncertainty and potentially significant logistical problems, according to military and congressional leaders.

Without a bilateral accord, which is currently stalled by Afghan President Hamid Karzai (who negotiated the agreement in the first place), planning in Congress and at the Pentagon has become increasingly complex, affecting the overall defense budget and jeopardizing the ultimate success of the Afghan government.

Lawmakers have been asking pointed questions about Afghanistan planning in recent hearings whose sparse attendance reflects the diminishing attention being paid to the war effort.

“This is a serious hole in your budget here,” said Rodney Frelinghuysen, R-N.J., chairman of the House Defense Appropriations Subcommittee. “It’s difficult for us to put a bill together with that issue open.”

Frelinghuysen’s comments followed revelations last week that the Pentagon does not plan on providing a specific request for war-related operations until it is clear whether U.S. forces will remain in Afghanistan after 2014.

Pentagon Comptroller Robert F. Hale explained it would be difficult to finalize the budget details until a bilateral agreement with Afghanistan is finalized.

“When we get an enduring presence decision, as soon as we can after that, we will get a formal budget amendment to you for” the Overseas Contingency Operations fund, which is used to support the war and the wider war on terrorism, Hale said. “If that doesn’t work with the timing issue, then we’re gonna have to look at other options. And we are thinking of them now, as to how we proceed if we don’t get an enduring presence decision.”

Hale’s comments were the clearest indication that the Pentagon is not planning to make a specific OCO request until at least April, after the election of a new Afghan president.

U.S. military commanders hope to station between 8,000 and 12,000 U.S. troops, plus thousands of allied forces, in Afghanistan after 2014 if a security deal is finalized.

If the security pact is not signed, all U.S. and allied forces would depart Afghanistan by the end of the year.

This complicates congressional plans for Defense appropriations and authorization bills. Frelinghuysen said his panel needs to bring its bill up for a House vote this summer. This is particularly important in an election year, when lawmakers’ attention increasingly turn to their states and districts.

So far, the Pentagon has only provided a placeholder request of about $79 billion, which would be on top of the $495.6 billion base budget request sent to Congress earlier this month. Defense Secretary Chuck Hagel told the panel that it would be difficult to provide more details for the war budget without knowing how long U.S. forces would be asked to remain in Afghanistan.

“We believe we have a role and ought to have a role, a continued role in Afghanistan, train, assist, advise, counterterrorism, but that has to be done in coordination, first with the people of Afghanistan inviting us and agreeing,” Hagel said.

The Obama administration is expecting that the next president of Afghanistan will sign the bilateral agreement.

The war funding has been important to appropriators not only because it provides for U.S. operations overseas, but because it also has allowed appropriators to fund priorities that don’t fit into the spending caps that Congress placed on the base budget.

The OCO fund is exempt from those spending limits, which has allowed appropriators to shift as much as $8 billion of critical operations and maintenance funding to the fund in recent years.

With the likelihood that lawmakers will need to make further reductions to the president’s budget request — because it includes billions in reductions to personnel benefits and other changes Congress likely won’t support — the OCO fund is an important pressure relief valve.

Rep. Peter J. Visclosky of Indiana, ranking Democrat on the House Defense Appropriations panel, echoed Frelinghuysen’s concern. “As discussions take place with the president they have to understand there is some urgency here in terms of the appropriations process,” he said.

The absence of a bilateral agreement may also trigger a serious logistical problem for the U.S. military, which said its ability to extricate people and equipment from Afghanistan becomes far more challenging the longer it takes for a security deal to be finalized.

Senate Armed Services Chairman Carl Levin, D-Mich., said he supports the president’s decision to begin planning to pull out of Afghanistan entirely.

“I continue to believe that it is in our interest to continue supporting Afghanistan’s security forces beyond 2014 to secure the hard-won and impressive gains of the past decade,” Levin said.

When Levin asked U.S. Central Command chief Gen. Lloyd J. Austin III last week how long the United States can wait for an agreement, Austin said, “By mid-summer, we will experience moderate risk. As we go beyond that time frame, the risk increases substantially.”

Austin said that if the deal is not signed, “we will move rapidly to consider alternatives for continuing a security cooperation relationship with Afghanistan. Unfortunately, in the wake of such a precipitous departure, the Afghan government’s long term viability is likely to be at high risk and the odds of an upsurge in terrorists’ capability increases without continued substantial international economic and security assistance.”

Austin warned that a failure to complete the security pact could cause a breakdown in Afghanistan, as well as the entire region.

“Without our mentorship, we would immediately see a much less effective” Afghan force, Austin said. Later, Afghan forces would likely fracture.

“Regionally, we would see hedging as each country in that region moves to protect their interests. It would be somewhat destabilizing on the whole,” he added.